• A bull elk bugles in Yellowstone National Park

    Yellowstone

    National Park ID,MT,WY

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    The road linking West Thumb and Old Faithful is closed for the season—traffic should detour through West Thumb, Lake, and Canyon. More »

Hot Springs and How They Work

Emerald Spring glows green.

Emerald Spring

Hot springs with names like Morning Glory, Grand Prismatic, Abyss, Emerald, and Sapphire, glisten like jewels in a host of colors across the park's harsh volcanic plain. They are the most common hydrothermal features in the park.

Their plumbing has no constrictions. Superheated water cools as it reaches the surface, sinks, and is replaced by hotter water from below. This circulation, called convection, prevents water from reaching the temperature needed to set off an eruption. [View the anatomy of a hot spring.]

Did You Know?

Seventh Cavalry Ensignia Pin.

Prior to the establishment of the National Park Service, the U.S. Army protected Yellowstone between 1886 and 1918. Fort Yellowstone was established at Mammoth Hot Springs for that purpose.